Help our boys in Helmand by chipping in for choppers

Shakespeare told us that "the whirligig of time brings in his revenges" (Twelfth Night, 1601). It's believed he was referring to the helicopter, invented by Leonardo da Vinci in 1493, and operated in his design by four men pedalling frantically. Later there was a huge political row over the government's failure to deploy them in Calais, which fell to the French in 1558, though it has since been re-colonised by chains selling cheap wine to British drunks. In those days, the government dealt with its more annoying opponents by cutting off selected heads. This option is not open to Gordon Brown, so he has to argue in the Commons instead.

MPs wanted to be in frisky mood yesterday, since it was to be the last prime minister's questions until mid-October. When the Speaker announced at the start: "There is far too much noise in the chamber," someone said: "Hear, hear", and this grew to a great rumbling roistering cheer which seemed to carry on for an age. Not a dig at Mr Bercow, just high spirits.

These were dampened when David Cameron made it clear he wanted to talk about Afghanistan in general and helicopters in particular. Mr Brown insisted that the number of helicopters in theatre had risen by 60% over three years. The Tory leader insisted with equal vehemence that in this period the number of troops had doubled, so in effect it was a reduction. And, what was more, the US Marines, who have as many men in Helmand as us, had the use of 100 helicopters while we had only 30.

This was getting wearisome. It was exactly like the arguments over public spending: both sides can pick whichever figures they like and insist that if the other lot don't like them, they are evil liars who should be burned alive. Or something like that. The prime minister proudly announced that there was a "helicopter fund" which will provide helicopters for British soldiers. I liked the idea of that. Chuggers – charity muggers – would stop you in the street and ask for your bank account details. There would be shops: "The helicopter fund urgently needs clothes, books, CDs, good condition only ..." It turned out to mean that other countries are chipping in with helicopters. Or rather, they might: Mr Cameron pointed out that the fund had not yet supplied a single helicopter.

Both sides geared up for their planned perorations. The Tory leader saw no "relentless commitment". We were on our fourth defence secretary in three years, and the latest (you know, the one with the bottle-brush moustache) ranked just 21st out of 23 in the cabinet.

Mr Brown was left with the ejector seat. "I hoped that we had escaped party politics ... owe a duty to our forces ... brave, courageous, professional, determined." Praise them to the skies, then accuse the other side of abandoning them. I suppose that's what Shakespeare meant by revenges.